Exactly. And women from some religious/ethnic backgrounds do have real health problems due to lack of exercise as they cannot attend classes or swimming sessions where men are present. So why not be tolerant and give them space.
If you particularly want a 'bums and tums' or Zumba - why not attend classes which are mixed. Or ask for men-only classes? Now there are no men-only classes generally because the demand isn't there, not out of discrimination.
Some of my women friends who play golf where NOT ALLOWED to have full membership, and could only play off-peak, and leave peak times for the men 'who were working hard keeping those little women in luxuries'. Some of those women friends were dentists, doctors, business owners, etc. It is only when the Club took a downturn in membership that the rules were relaxed (: